Feat v0.7.7 API tokens + extension permissions (#61)

Personal access tokens (PATs) for programmatic API access with
SHA-256 hashing, permission scoping (git model), and Settings/Admin UI.
Extension-declared user permissions with dynamic registry, gate_permission
manifest field, permissions Starlark module, and grouped admin UI.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,42 @@
 
 All notable changes to Armature are documented here.
 
+## v0.7.7 — API Tokens + Extension Permissions
+
+Personal access tokens (PATs) for programmatic API access, plus extension-declared
+user permissions for backend RBAC enforcement.
+
+**API Tokens (PATs)**
+
+- Migration 015: `api_tokens` table (PG + SQLite) with SHA-256 hash, prefix, JSON permissions, expiry
+- Token store interface + PG/SQLite implementations (Create, GetByHash, ListForUser, Revoke, CleanExpired, UpdateLastUsed)
+- `POST /api/v1/auth/tokens` — create token (returns plaintext once), permissions validated as subset of user's
+- `GET /api/v1/auth/tokens` — list my tokens; `DELETE /api/v1/auth/tokens/:id` — revoke
+- `POST /api/v1/admin/tokens` — create token for any user (audit logged as `admin.token.create`)
+- Auth middleware: `Bearer arm_pat_...` tokens validated alongside JWTs, user active check, fire-and-forget `last_used_at` update
+- Permission scoping: PAT permissions used directly at request time (git model — retained until revoked)
+- `auth.HashToken()` shared SHA-256 utility (replaces local `hashToken()` in auth.go)
+- Settings UI: API Tokens tab with create form, permission checkboxes, copy-once display, revoke button
+- Admin UI: "PAT" button on user rows creates tokens for any user
+- `BootstrapPAT`: `ARMATURE_BOOTSTRAP_PAT=true` env var creates admin PAT at startup, writes to `/tmp/armature-admin-pat.txt`
+- E2E smoke test: reads bootstrap PAT before falling back to login flow
+
+**Extension-Declared User Permissions**
+
+- Dynamic permission registry: `RegisterExtensionPermissions()` / `UnregisterExtensionPermissions()` with RWMutex
+- `AllPermissionsWithExtensions()` returns kernel + extension permissions; `AllPermissionsGrouped()` for admin UI
+- `user_permissions` manifest field: extensions declare user-facing permissions
+- `gate_permission` manifest field: ext_api.go checks user permission before calling `on_request`
+- `req["permissions"]` in Starlark request dict: user's effective permissions included for inline checks
+- `permissions.check(user_id, perm)` Starlark module: read-only permission check, always available (no sandbox gate)
+- Group UI: permissions grouped by source (Platform / package name) with section headings
+- Boot-time scan: `RegisterAllExtensionUserPermissions()` populates registry from active packages
+- Uninstall cleanup: `UnregisterExtensionPermissions()` called on package delete
+
+**Tests:** 10 new tests (7 handler + 3 auth registry)
+
+---
+
 ## v0.7.6 — Code Hygiene + Test Coverage
 
 **Critical Fixes**